There are times in a photographer’s life when reflections in glasses is just a fact of life. Most of the time we can eliminate them in-camera, especially with a posed session. Occasionally, that’s not possible. Perhaps when in very confined space with a huge softbox.
There are techniques to help get rid of it in post, though. Although it does require some pre-thought during shooting and taking an extra shot. This video from photographer Bill Larkin, shows his quick method for removing glare and reflections from glasses in Photoshop.